Magnetite is a ferrimagnetic mineral with the chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron(II, III)oxide.
Several methods are known in the art for the synthesis of magnetite. R. M. Cornwell and U. Schwertmann, “The Iron Oxides.Structure, Properties, Reactions, Occurance and Uses.” Sec. Ed., WILLEY-VCH, Weinheim, 2000, have reported several synthetic methods all of which require more than one iron compound as precursor, several chemical reagents, inert atmosphere, special apparatus and/or other restricting conditions. Exemplary methods are:
                c) Reduction of hematite at 400° C. in an atmosphere of 5% H2/95% Ar, saturated with water vapour free of O2         d) Reaction of a 1:2 FeII/FeIII solution, under alkaline conditions at 80° C. under N2         e) Reaction at 85° C. of FeII ammonium sulphate solution (buffered to pH 7-8 with sodium acetate) with hydroxylamine sulphate; the suspension is held under N2 gas3Fe2++NH3OH++3H2O→Fe3O4+NH4++6H+        f) Reductive transformation in a sealed ampoule of an akaganeite suspension in the presence of hydrazine at pH 9.5-1.5 and 100° C.12β-FeOOH+N2H2→4Fe3O4+8H2O+N2         g) Decomposition of an alkaline (0.2-0.4MOH) solution of FeIIINTA at 217° C. in an autoclave,        h) Heating of iron hydroxide acetate at 200-260° C. under N2         i) Boiling a mixture of FeII sulphate and bispyridoxylidene hydrazine phthalazinc for 10 min. at pH7        j) Thermal decomposition of FeII sulphide in air at 500° C.3FeS2+5O2→Fe3O4+3S+3SO2         k) Holding a solution of FeII acetylacetonate in 1-propanol under N2 in an auto-clave at 300° C. for several hours        l) Reduction of nitrobenzene to aniline produces Fe3O4;        

Further, methods for preparing magnetite are also known from U.S. Pat. No. 2,537,699, U.S. Pat. No. 4,311,684, U.S. Pat. No. 4,886,752 and U.S. Pat. No. 6,767,635B1.